Unable to fire laser

LightBurn Hardware Compatibility GRBL
1

Hi, been struggling for some time now and would really appreciate any help to get this laser working.
I have an Optlaser PLH3D-XT8 45w laser fitted to an Ooznest workbee 1500x1500 router.
As far as I can see, I can’t control the router with lightburn and have to export Gcode to it. I have managed to cut out a very basic square and have the Gcode file for that which appears to work, but anything else I’ve tried just traces the shapes without actually firing the laser. I have tried copying the header and footer from my succesful cut and put it into the other cuts, but still doesn,t work. I have spoke to Optlaser but they basically said they were not lightburn experts, so I should try here.
ltest2.gcode (601 Bytes)
porschetest.gc (37.7 KB)
The 2 files attached are the succesful one ltest2, and 1 of many that don’t work.

Regards, Ben

2

Those two appear to be contradictory. If LightBurn can connect to the controller and it “traces the shapes”, then it can “control the router”. Firing the laser is a separate problem if the machine is moving properly under LightBurn’s control.

This G-Code line (apparently) sets the laser to use 255 PWM power levels:

M452 C"!exp.heater3" R255  F1000

Did you set LightBurn’s S-Value Max to 255?

The ltest2 file has :

G0 X43.7141 Y19.0000 Z1.0000 F10000 S0
G1 Y0.0000 F1000 S255
G1 X0.0000 S255

Which suggests Emit S Value With Every G1 Command is turned on. That is not the case in the porschetest file:

G0 X51.678Y55.72
; Layer C00
G1 X49.665Y52.519S235.9F6000
G1 X45Y44.878

A feed of 6000 mm/min = 100 mm/s for a vector file seems extremely aggressive for a vector file on what looks like a leadscrew machine. If it’s similar to that machine, then the limit seems to be 2500 mm/min.

The description suggests the controller runs RepRapFirmware, so (IIRC) it will scale the power downward when it can’t reach the commanded speed. That will reduce the power to less than half of what you expect, even if changing the Emit S Value setting gets it working.

Tweak those settings and, if the situation doesn’t improve, upload one of the lbrn2 files with screenshots of the Cuts and Layers window to give the hive mind something to think about.

3

Thank you very much, will take me a little time to digest all that and apply it as I’m a complete laser newbie.
I think I misled you with the first bit, what I meant was, I believe I cannot control the router directly from lightburn, only by using it to generate the Gcode then use on my router as normal. For both these files this is what I was doing, but the very basic test is the only one that fires the laser. The second one appears to trace the shape. I will work though your reccomendations and see how that goes. Thank you very much for your advice.

Regards, Ben

4

It’s not entirely obvious which device type will match whatever firmware the controller is running, but it sounds like a Marlin descendant. If you haven’t already gotten it connected, start with Marlin to see if starts behaving.

Plain old GRBL would be the next choice, but you may need full-frontal tweakage with a Custom G-Code device.